A workshop in the bone-implant interface is proposed, to be held in Chicago in the fall, 1983. The state of the art will be reviewed in presentations and discussions. Critical questions will be identified and research directions suggested in discussion workshops. A written report of the review presentations and workshop results will be prepared and published. Clinical loosening is the major cause of failure of total joint replacements. Progress has been made on reducing the loosening incidence, but further progress is prevented by poor understanding of the conditions at the bone-implant interface, where the loosening process occurs. The interface problem is the major problem area in need of clarification in total joint failure. Although there is much ongoing research related to the interface, the critical questions are unclear and it is likely that new approaches are needed. It is appropriate at this time to review what is known about the bone-implant interface, identify critical questions, and suggest needed research directions. This can best be done by a focused conference of clinical and basic investigators from a multi-disciplinary background. Such a conference would be a significant contribution to more reliable total joint replacements.